Task 8: Smart Sensors for Real-Time Measurement

SUSTAIN Task 8: Smart Sensors for Real-Time Measurement

Prof. Claire Davis, Dr Frank Zhou

Improved monitoring of steel production allows for greater digitalisation and control, leading to more efficient, less energy-intensive manufacturing.

Improved monitoring of processes is a key part of sustainability, growth and modernisation for the steel industry. 

Significant improvements have been made for real-time monitoring and feedback control, but several areas have been highlighted where insufficient information is currently available, requiring new and improved sensing approaches.

One area is microstructural monitoring during processing, and electromagnetic (EM) sensors are ideal candidates. The project focuses on the development of new EM sensors and signal-microstructure relationships for use in steel processing. 

The Task 8 project has included the design, build and installation of an EM sensor array into a furnace-run-out table for phase transformation monitoring during cooling.

Finite element modelling and experimental validation has been carried out to link the sensor signals to magnetic properties and microstructures for specific complex geometry steel products (wire/rod and narrow strip). 

In addition to the steel product-focused work, the project has also included developing an improved fundamental understanding of the link between magnetic signals and steel microstructure, including changes in magnetic signals with temperature.


The project started with developing a new EM sensor array system to measure steel grades with more complex geometries than previous work on sensors for wide strip steels. 

The new array system built upon the knowledge gained in earlier collaborative work with the University of Manchester, Primetals Technology Limited and Tata Steel on the now commercial EMspec system. The four-sensor head approach in the array required detailed modelling to optimize the design and avoid interference between the sensor heads. The modelling stage progressed very well with a proposed design that was contracted out for the build phase. The new hardware was received and installed in the laboratory furnace-roller table for trials, following validation of the modelling tests. 

In parallel to the sensor array development, more fundamental studies on the effect of temperature on the magnetic properties of steels have been pursued.

There has been some shift in the plan during the project to account for additional opportunities that arose. For example, the task researcher Dr Frank Zhou split his time equally between the main Task 8 project and an industrial contract with Primetals Technology Limited (PTL) for 12 months focusing on modelling the commercial EMspec sensor system, and supporting PTL in signal interpretation. This benefitted the main Task 8 project in understanding the sensor signal–sample geometry effects.

Dr Zhou also successfully obtained a SUSTAIN ECR grant (on the effect of temperature and magnetic field on domain wall movement) in February 2021 for 12 months at 0.5 FTE and a TFI ECR grant (on atomistic scale simulation of the magnetic anisotropy in steels) in June 2022 for 6 months at 0.5 FTE. Both ECR projects focus on some specific aspects of fundamental understanding, which align well with one of Task 8’s aims to improve fundamental understanding of the link between magnetic signals and microstructure. 

These parallel funded activities allowed the overall Task 8 project end date to be extended providing continuity.

Key findings

A new four-EM sensor head array system has been designed, built and installed in the lab furnace-roller table at WMG, University of Warwick. 

The sensor array finite element model has been developed and validated for samples with known magnetic properties. This allows the EM sensor signal to be correlated to the magnetic properties, and hence microstructures, for specific complex geometry steel products (wire/rod and narrow strip). The results to date have identified a suitable sensor array design to allow improved spatial resolution of the signals.  

A high-temperature cylindrical-shaped EM sensor was used to demonstrate the capability of the EM sensor approach to monitor recovery and recrystallisation for IF steel in-situ during annealing heat treatment. The results provided proof of concept for in-situ measurements at high temperatures and supported new project proposals.

Through the ECR project, in-situ magnetic domain observation using Lorentz microscopy in the TEM with a high-temperature sample holder has been completed showing domain movement under changing magnetic fields and temperature. It was found that increasing both magnetic field and temperature allows magnetic domain walls to overcome pinning features. This is the first time both temperature and magnetic field effects on domain wall movement have been observed for structural steel grades and supports understanding for the effects of temperature.

High-temperature magnetic property measurements were carried out using a high-temperature Epstein frame setup, for full BH behaviours. The work was carried out with the University of Manchester and is part of an ongoing collaboration for EM sensor developments. The measured results will be used in models for sensor-microstructure transformation monitoring and to examine the effects of microstructural parameters.

Industrial applications

Commercial EM sensor systems are already used for cold strip steel monitoring, with signals correlated to mechanical properties. Currently, the only commercial system for hot strip steel microstructural monitoring (phase transformations on the run-out table) is the EMspec system, produced by Primetals Technology Limited. 

There are currently no EMspec systems used in the UK; the lab scale demonstration furnace-roller table with sensor developed at WMG, along with the modelling and signal interpretation knowledge will support any installations in the future. 

There is a need to extend knowledge and application of sensors to non-strip steel geometries and grades. Potential impact will therefore arise from the use of EM sensor arrays designed for complex geometries in the UK steel mills. The sensor array prototype system has been built and room temperature validation completed. The next stage is lab tests for high-temperature phase transformation monitoring for steel grades of interest for narrow strip and rod.

The underpinning knowledge is now proven, therefore the route to impact is for industrial trials and signal interpretation. Funding has been secured to build two additional sensor array systems (SUSTAIN Technology Transfer Fund and High Value Manufacturing Catapult, HVMC) and further funds have been won (HVMC) for the installation of the sensors into steel mills (planned with British Steel and Liberty Steel).

The proof of concept work for monitoring of microstructural changes in-situ at high temperature (recovery / recrystallisation and tempering / spheroidization) has led to further funding (EPSRC Instrumentation grant) to develop high-temperature sensors, working with the University of Manchester. These are being considered as laboratory systems and potential industrial concept systems (that could be used in annealing furnaces).

Looking ahead

The next stages of the sensor array work are trials in the laboratory furnace–roller table followed by industrial trials, for which funding is secured.

The next stage of the fundamental scientific study on the effect of temperature and microstructural parameters (of particular interest is precipitates in low alloy steels which have not been quantitatively studied before) on the magnetic behaviour of steel.

A combined modelling and experimental approach is needed considering the full magnetic response (BH curves) of the steel. Funding has not been secured for this activity, although Dr Zhou has submitted an EPSRC Fellowship application to develop this area.

The effects of electrification

Planned electrification of steelmaking is expected to have an impact on the chemical composition of the steel grades produced, for example through an increase in residual element content. 

Changes in composition will affect the metallurgical behaviour of the steel, for example phase transformation and recrystallisation kinetics, which may require changes in the thermo-mechanical processing parameters. 

Smart sensors that can monitor microstructural changes can be used with mill models and other measured data to provide feedback control to support the optimisation of mill schedules and reduce scrappage / downgrading rates.

Further reading
  1. Kahrobaee, S., Ahadi Akhlaghi, I., Davis, C., & Zhou, L. (2022). Detection of Decarburising Depth in Hadfield Steels Using a Multi-magnetic NDE Method. Nondestructive Testing and Evaluation, 37(4), 482–494. https://doi.org/10.1080/10589759.2022.2038150
  2. Wilson, J. W., Zhou, L., Davis, C. L., & Peyton, A. J. (2021). High temperature magnetic characterisation of structural steels using Epstein frame. Measurement Science and Technology, 32(12). https://doi.org/10.1088/1361-6501/ac17fa
  3. Zhou, L., Wu, F., Hall, R., & Davis, C. (2022). Electromagnetic sensors for in-situ dynamic microstructure monitoring of recovery and recrystallisation in interstitial free steels. Journal of Magnetism and Magnetic Materials, 551. https://doi.org/10.1016/j.jmmm.2022.169187
  4. Jones, B. L., Jolfaei, M. A., Hobson, S., Rainforth, W. M., & Davis, C. L. (2022). Magnetic characterisation of strain ageing in near eutectoid drawn pearlitic wire using an electromagnetic (EM) sensor. Engineering Failure Analysis, 131. https://doi.org/10.1016/j.engfailanal.2021.105909

About the author

Latest articles

Featured article
  • Women with Metal

    Women with Metal

    It’s been 7 weeks since the first Women with Metal event and the 2nd edition of this sell out conference has already been booked top take place on 29 October 2024. Kirsty is increasing the size and scale of the event and has booked a hall at the ICC Birmingham for year 2 with the…

    Read article →

  • Organized Crime Drives Metal Theft Epidemic: UK Economy Loses Half a Billion Annually.

    Organized Crime Drives Metal Theft Epidemic: UK Economy Loses Half a Billion Annually.

    A newly released report by the All-Party Parliamentary Group on Metal, Stone, and Heritage reveals that metal theft orchestrated by organized crime groups is costing the UK economy a staggering half a billion pounds each year. The comprehensive study, titled “Tackling Metal Theft,” exposes a rising trend in metal-related crimes since 2019, amounting to a…

    Read article →

  • Van Leeuwen: The Energy Project

    Van Leeuwen: The Energy Project

    In December 2021 Jill Clements told me about the Energy Project that had been signed off by Van Leeuwen UK. Jill was animated when talking about the news, and excitedly explained the potential that this opened up to her and the team. “I am very excited about it. I am really happy that finally we…

    Read article →

  • Drywall Steel Sections Secures £9.5 Million WMCA Investment

    Drywall Steel Sections Secures £9.5 Million WMCA Investment

    £13 million was all it took for a family run manufacturing business to make a monumental transformation in the historic heart of the steel industry! Drywall Steel Sections Ltd are on the move after securing loan funding of £9.5 million from the West Midlands Combined Authority (WMCA). Their Cradley Heath site was no longer fit…

    Read article →

  • The NASS Golf day & Summer Gathering 2023

    The NASS Golf day & Summer Gathering 2023

    On the 29th of June, Matt Tipper, Stewart Andrews and I had a swing of the clubs at Priory Breadsall in Derby. A week later, on the 6th of July, I attended the Summer Gathering in central Birmingham. Two entirely different events, seven days apart, both hosted by The National Association of Steel Service Centres…

    Read article →

  • The Stainless Steel Industry Meets at the BSSA Annual Conference & Dinner

    The Stainless Steel Industry Meets at the BSSA Annual Conference & Dinner

    The British Stainless Steel Association (BSSA) met at The Grand Hotel in Birmingham in May 2023 for their annual conference and dinner. Having attended the last four BSSA annual conferences and this year’s Food and Beverage Industry event (link to article), it was great to catch up with familiar faces from the industry and new…

    Read article →

  • Q2 Review: Analysing The Recruitment Landscape

    Q2 Review: Analysing The Recruitment Landscape

    Large corporate companies are facing challenges attracting new talent and retaining skilled staff especially when their salary structures, work flexibility and staff benefits are outdated compared to smaller, more agile SMEs. Smaller companies can have the advantage of being able to offer more flexibility and quicker decision-making, meaning they’re a more appealing option for certain…

    Read article →

  • How to use LinkedIn for YOUR Metal Business.

    How to use LinkedIn for YOUR Metal Business.

    The below presentation was given at the National Association of Steel Service Centres (NASS) 2023 Summer Gathering. In 12 days I’ll have been using LinkedIn for 12 years! On the day I joined I thought: “Wow! This business Facebook thingy is incredible! Everyone I want to do business with is right here, this will be…

    Read article →

  • Leading the Charge: Steel Dynamics in the Nuclear Industry

    Leading the Charge: Steel Dynamics in the Nuclear Industry

    Prime Minister Rishi Sunak recently unveiled the Great British Nuclear initiative, marking a significant milestone in the UK’s pursuit of a sustainable energy future. With nuclear power playing a crucialrole in achieving net-zero emissions and reducing greenhouse gases, this announcement signals a remarkable leap forward in the nation’s commitment to clean and reliable energy sources.…

    Read article →

  • Steel Dynamics Group Ltd. Acquires Ferrari Stainless & Alloys.

    Steel Dynamics Group Ltd. Acquires Ferrari Stainless & Alloys.

    Steel Dynamics Group Ltd. Acquires Ferrari Stainless & Alloys Ltd. Launching P&P Non Ferrous: A Gateway to Enhanced Customer Services and Expansion Down South In a strategic move to bolster its position in the industry, Steel Dynamics Group Ltd. proudly announces the successful acquisition of Ferrari Stainless & Alloys Ltd. in Wimborne. This transformative development…

    Read article →

  • Sustainability is key to modern manufacturing

    Sustainability is key to modern manufacturing

    During my time supplying specialist metals into the manufacturing sector, I have noticed several things regarding the supply chain local to me in South Yorkshire. 1 Large Manufacturing companies often have difficult onboarding processes.  This makes it difficult for smaller SMES or new market entrants to be able to supply them. 2 Manufacturing companies are…

    Read article →

  • Lasers: The Tesla of Tooling

    Lasers: The Tesla of Tooling

    Welcome back, I’m LaserEd, and I work with lasers. I’ll be laser-educating for The Metal Magazine and I hope it results in more metal parts being lasered! First of all, I haven’t had an accident after writing my last article about Laser Safety. I have been busy researching. Although it is time consuming, I love…

    Read article →

  • Implementing QMS Certifications for Small Businesses and Start-Up Companies

    Implementing QMS Certifications for Small Businesses and Start-Up Companies

    Welcome to the fourth and final instalment of this short series on Quality Management System certification for small businesses and start-up companies. In this 4 part series I have been explaining exactly what third-party certification involves, and how you can level up your business through this process. The standard we are focussing on is ISO9001:2015, as…

    Read article →

Get notified when we publish new articles!

Want to feature in the next edition?